Now if you call a function, swap like increment or cube or swap, or in this case, foo, those variables are the parameters to that function, end up getting stored next in memory.

The paper points out that in order to make the dummy discrete data sheet, it is necessary to setup increment modulator and delay memory, along with the function of convolution.

You then increment the pointer, which makes it point to uninitialized memory, which just happens to have a zero in it.